1. Technical Field of the Invention
The present invention relates to a fan unit that has various uses including electric vehicles, airships, turbine engines, turbine generators, fuel batteries, air conditioners, heat exchangers, and fluid sensor, and in particular, to the fan unit having a motor equipped with a rotor and fins united with the rotor itself.
2. Related Art
Conventionally, a variety of types of fan units have been used. One type of fan unit has been proposed by Japanese Patent Laid-open No. 11-218092, in which a compact fan with a brushless compact DC motor is explained. Specifically, the fan unit is made compact to the extent of allowing the fan unit to be directly disposed on, for example, a printed wiring assembly. This fan unit has a feature that a brushless DC motor driving a fan wheel is provided as a single-phase single-winding gearing-pole type of motor provided with a non-feedback permanent magnet rotor and at least one magnet for positioning is placed to exert an influence on an activating position of the rotor.
However the above conventional fan unit faces a problem that the motor is obliged to position at the center of a flow path for fluid in which the fan unit is arranged. Hence it is unavoidable that the motor becomes resistance against a flow of fluid.
In addition, due to the fact that the foregoing conventional fan unit has a driving part located in the flow path, there are various other difficulties to the fan unit. For example, there is a reduction in fluid delivery efficiency, fluid loss is easily caused, and the flow path is difficult to be thinner in construction. Moreover, some kind of restrictions in temperature and types of gas and solvent are easily exerted on the fluid. In cases where the driving part becomes a resistance against the flow of fluid and dirt in the fluid adheres to the driving part, the efficiency of fluid flow will suffer a further decrease.